Online social networks are ubiquitous in today's society, enabling hundreds of millions of users to create and build relationships electronically via the Internet using any of a variety of user devices (e.g., personal computers, laptops, tablets, smart phones, etc.). Users may join a social network using registration process. But many social networks allow users to register anonymously or with limited means of verifying the identity of registrants, thereby failing to prevent many users from registering with false information. Although anonymity is welcomed in some social networks, accurate identification can be crucial in others. On-line social networks that facilitate in-person meetings between users, for example, have an interest in ensuring accurate information is collected—especially if its users include minors.